This invention relates to coating systems for facilitating the application of a coating to a surface wherein the coating is polyurethane or other material of the type in which the coating material needs to be mixed with another coating material such as a catalyst immediately prior to the application of the coating to a surface. Polyurethane paint and primer is typically used in painting aircraft. When such a coating is used, the coating and the catalyst should be kept in sealed containers until they are mixed and then the coating should be applied to the surface to be coated soon after mixing. The amount of catalyst to be used with the paint or primer must be precisely in the correct proportions to provide satisfactory results. The coating process presents a problem when the coating project is merely a touch up application in which a very small surface area is to be covered. When a conventional container of polyurethane coating material is opened along with the catalyst, precise amounts of the coating and catalyst have to be measured out and mixed. Precision in the amounts of the mixed components is difficult, because some of the measured amounts remain coated on the walls of the measuring vessel instead of winding up in the mixture. In a touch up application, only very small amounts of the polyurethane coating material and catalyst will be needed, so the remainder of the coating material and catalyst in the open containers will typically be wasted. In addition the unused parts of the coating material and catalyst must be disposed of. Often the unused coating material is hazardous waste which requires documented disposal. In addition care often must be taken to avoid unsafe contact of the coating material with the persons using the material.
The present invention overcomes the problems associated with touch up applications by means of a unique packaging technology in which a small amount of the uncatalyzed paint or primer is contained in an outer container and the catalyst is contained in an inner container within the outer container. The top of the inner container is closed with a puncturable seal and the bottom of the inner container is closed with a seal which is designed to completely detach from the inner container in response to downward pressure from within the inner container. The inner container nests within the mouth of the outer container and the two containers combined are closed with a cap which screws onto the neck of the outer container. The inner container when closed with the cap of the outer container makes an air tight seal with the neck of the outer container thereby providing a sealed enclosure around the paint or primer within the outer container.
To use the paint kit, the cap is removed and the inlet tube of an aerosol spray canister is manipulated to puncture the upper seal on the inner container and is inserted through the inner container to engage the lower seal closing the bottom of the inner container. The aerosol inlet tube is pushed downwardly against the lower seal causing it to completely detach from the lower end of the inner container and allowing the catalyst to drop into the paint or primer in the outer container. The lower end of the canister is provided with a mounting structure which screws onto the neck of the outer container. After the lower seal is dislodged from the inner container, the mounting structure is screwed onto the neck of the outer container, whereupon the combined containers are vigorously shaken to thoroughly mix the catalyst and the paint or primer in the exact proportions for satisfactory use. Because the material coating the walls of the nested container becomes thoroughly mixed in the vigorous shaking, the precision of the amounts of the mixed components is achieved even though only small quantities are mixed.
By actuating the aerosol spray canister, the mixed catalyst and paint or primer can then be sprayed onto the surface to be coated in the touch up application.
Following the touch up painting operation, the aerosol canister is removed from the inner and outer containers and the material within the inner and outer container is allowed to dry. The containers with the dried unused coating materials can be then disposed of in accordance with local disposal regulations. Because the two containers contain the exact proportions of the catalyst and paint or primer needed and contain these proportions in only small amounts, the problem of waste and waste disposal is avoided, while at the same time ease and convenience in carrying out the touch up painting operation is achieved with limited risk of the coating material coming into contact with the user.
The two part container described above can also be used with a brush to carry out the touch up painting application.